A friend of mine had a PSU blow in the middle of other rotten luck, so I have him my PCP&C Silencer 910w and bought a SeaSonic SS-660XP2 (660W 80+ Platinum) as the replacement. It's a much lower-powered unit, but my stock i7 2600k and 780GTX shouldn't be a challenge. My system typically draws 130W and can get up to around 380w when heavily loaded.

The new power supply works without a problem with an old fanless Geforce 9600GT video card, but with the GTX780, it plays dead. The mobo's power LED illuminates, but the cooling fans don't even nudge. Nothing.

With the older card, I can run OCCT (video card stress test) plus Prime95 all day I doubt a simple POST with the GTX780 takes more power than that, especially since the 780 uses minimal power when not loaded.

I've tried the obvious:

Different PCIe power cables

PCIe power cables in different modular outputs (though it's a single 12V rail, so no matter)

All cables and the card are seated properly

Different PCIe slot

Disconnect unessential hardware

Flipped PSU's power switch rapidly (rec. by Seasonic)

Checked voltages (5.000v and 12.12v)

I've already ordered an exchange for the same unit, but I am curious about ideas others may have. I'm far from unfamiliar with computer hardware, but this is a new one on me!